PROGRESS TOWARDS A LONG LENGTH METALLIC PRECURSOR PROCESS FOR MULTIFILAMENT BI-2223 COMPOSITE SUPERCONDUCTORS

A process based on mental precursors has been developed for fabricatin g 361-filament Bi-2223 oxide superconductor - silver composite tapes w ith oxide and whole wire critical current densities of 20.8 kA/cm(2) a nd 3.74 kA/cm(2) at 77 K over 85 m (1 mu V/cm criterion). Fabrication of approximately 50 m lengths for a cummulative 1 km yield average oxi de critical current densities of 15.2 kA/cm(2) and 11.9 kA/cm(2) using 1 mu V/cm and 10(-11) Omega cm criteria. Within tape Ic variability w as less than 5% except for Ic drop-offs near the tape ends. The oxide superconductor exhibited a high degree of the required texture. A 1.12 T (at 4.2 K) instrumented magnet with a 2.5 cm bore was fabricated by a react- and-wind approach from the tapes and delivered to Oak Ridge National Laboratory for quench studies.